pipeline.py

# Copyright 2024 The HuggingFace Team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from typing import List, Optional, Union

import PIL.Image
import torch
import torch.nn.functional as F
from transformers import CLIPTextModel, CLIPTextModelWithProjection, CLIPTokenizer

from controlnet_union import ControlNetModel_Union
from diffusers.image_processor import PipelineImageInput, VaeImageProcessor
from diffusers.models import AutoencoderKL, UNet2DConditionModel
from diffusers.pipelines.pipeline_utils import DiffusionPipeline, StableDiffusionMixin
from diffusers.schedulers import KarrasDiffusionSchedulers
from diffusers.utils.torch_utils import randn_tensor


def retrieve_timesteps(
    scheduler,
    num_inference_steps: Optional[int] = None,
    device: Optional[Union[str, torch.device]] = None,
    **kwargs,
):
    scheduler.set_timesteps(num_inference_steps, device=device, **kwargs)
    timesteps = scheduler.timesteps

    return timesteps, num_inference_steps


class StableDiffusionXLControlNetPipeline(DiffusionPipeline, StableDiffusionMixin):
    model_cpu_offload_seq = "text_encoder->text_encoder_2->unet->vae"
    _optional_components = [
        "tokenizer",
        "tokenizer_2",
        "text_encoder",
        "text_encoder_2",
    ]

    def __init__(
        self,
        vae: AutoencoderKL,
        text_encoder: CLIPTextModel,
        text_encoder_2: CLIPTextModelWithProjection,
        tokenizer: CLIPTokenizer,
        tokenizer_2: CLIPTokenizer,
        unet: UNet2DConditionModel,
        controlnet: ControlNetModel_Union,
        scheduler: KarrasDiffusionSchedulers,
        force_zeros_for_empty_prompt: bool = True,
    ):
        super().__init__()

        self.register_modules(
            vae=vae,
            text_encoder=text_encoder,
            text_encoder_2=text_encoder_2,
            tokenizer=tokenizer,
            tokenizer_2=tokenizer_2,
            unet=unet,
            controlnet=controlnet,
            scheduler=scheduler,
        )
        self.vae_scale_factor = 2 ** (len(self.vae.config.block_out_channels) - 1)
        self.image_processor = VaeImageProcessor(vae_scale_factor=self.vae_scale_factor, do_convert_rgb=True)
        self.control_image_processor = VaeImageProcessor(
            vae_scale_factor=self.vae_scale_factor,
            do_convert_rgb=True,
            do_normalize=False,
        )

        self.register_to_config(force_zeros_for_empty_prompt=force_zeros_for_empty_prompt)

    def encode_prompt(
        self,
        prompt: str,
        device: Optional[torch.device] = None,
        do_classifier_free_guidance: bool = True,
    ):
        device = device or self._execution_device
        prompt = [prompt] if isinstance(prompt, str) else prompt

        if prompt is not None:
            batch_size = len(prompt)

        # Define tokenizers and text encoders
        tokenizers = [self.tokenizer, self.tokenizer_2] if self.tokenizer is not None else [self.tokenizer_2]
        text_encoders = (
            [self.text_encoder, self.text_encoder_2] if self.text_encoder is not None else [self.text_encoder_2]
        )

        prompt_2 = prompt
        prompt_2 = [prompt_2] if isinstance(prompt_2, str) else prompt_2

        # textual inversion: process multi-vector tokens if necessary
        prompt_embeds_list = []
        prompts = [prompt, prompt_2]
        for prompt, tokenizer, text_encoder in zip(prompts, tokenizers, text_encoders):
            text_inputs = tokenizer(
                prompt,
                padding="max_length",
                max_length=tokenizer.model_max_length,
                truncation=True,
                return_tensors="pt",
            )

            text_input_ids = text_inputs.input_ids

            prompt_embeds = text_encoder(text_input_ids.to(device), output_hidden_states=True)

            # We are only ALWAYS interested in the pooled output of the final text encoder
            pooled_prompt_embeds = prompt_embeds[0]
            prompt_embeds = prompt_embeds.hidden_states[-2]
            prompt_embeds_list.append(prompt_embeds)

        prompt_embeds = torch.concat(prompt_embeds_list, dim=-1)

        # get unconditional embeddings for classifier free guidance
        zero_out_negative_prompt = True
        negative_prompt_embeds = None
        negative_pooled_prompt_embeds = None

        if do_classifier_free_guidance and zero_out_negative_prompt:
            negative_prompt_embeds = torch.zeros_like(prompt_embeds)
            negative_pooled_prompt_embeds = torch.zeros_like(pooled_prompt_embeds)
        elif do_classifier_free_guidance and negative_prompt_embeds is None:
            negative_prompt = ""
            negative_prompt_2 = negative_prompt

            # normalize str to list
            negative_prompt = batch_size * [negative_prompt] if isinstance(negative_prompt, str) else negative_prompt
            negative_prompt_2 = (
                batch_size * [negative_prompt_2] if isinstance(negative_prompt_2, str) else negative_prompt_2
            )

            uncond_tokens: List[str]
            if prompt is not None and type(prompt) is not type(negative_prompt):
                raise TypeError(
                    f"`negative_prompt` should be the same type to `prompt`, but got {type(negative_prompt)} !="
                    f" {type(prompt)}."
                )
            elif batch_size != len(negative_prompt):
                raise ValueError(
                    f"`negative_prompt`: {negative_prompt} has batch size {len(negative_prompt)}, but `prompt`:"
                    f" {prompt} has batch size {batch_size}. Please make sure that passed `negative_prompt` matches"
                    " the batch size of `prompt`."
                )
            else:
                uncond_tokens = [negative_prompt, negative_prompt_2]

            negative_prompt_embeds_list = []
            for negative_prompt, tokenizer, text_encoder in zip(uncond_tokens, tokenizers, text_encoders):
                max_length = prompt_embeds.shape[1]
                uncond_input = tokenizer(
                    negative_prompt,
                    padding="max_length",
                    max_length=max_length,
                    truncation=True,
                    return_tensors="pt",
                )

                negative_prompt_embeds = text_encoder(
                    uncond_input.input_ids.to(device),
                    output_hidden_states=True,
                )
                # We are only ALWAYS interested in the pooled output of the final text encoder
                negative_pooled_prompt_embeds = negative_prompt_embeds[0]
                negative_prompt_embeds = negative_prompt_embeds.hidden_states[-2]

                negative_prompt_embeds_list.append(negative_prompt_embeds)

            negative_prompt_embeds = torch.concat(negative_prompt_embeds_list, dim=-1)

        prompt_embeds = prompt_embeds.to(dtype=self.text_encoder_2.dtype, device=device)

        bs_embed, seq_len, _ = prompt_embeds.shape
        # duplicate text embeddings for each generation per prompt, using mps friendly method
        prompt_embeds = prompt_embeds.repeat(1, 1, 1)
        prompt_embeds = prompt_embeds.view(bs_embed * 1, seq_len, -1)

        if do_classifier_free_guidance:
            # duplicate unconditional embeddings for each generation per prompt, using mps friendly method
            seq_len = negative_prompt_embeds.shape[1]

            if self.text_encoder_2 is not None:
                negative_prompt_embeds = negative_prompt_embeds.to(dtype=self.text_encoder_2.dtype, device=device)
            else:
                negative_prompt_embeds = negative_prompt_embeds.to(dtype=self.unet.dtype, device=device)

            negative_prompt_embeds = negative_prompt_embeds.repeat(1, 1, 1)
            negative_prompt_embeds = negative_prompt_embeds.view(batch_size * 1, seq_len, -1)

        pooled_prompt_embeds = pooled_prompt_embeds.repeat(1, 1).view(bs_embed * 1, -1)
        if do_classifier_free_guidance:
            negative_pooled_prompt_embeds = negative_pooled_prompt_embeds.repeat(1, 1).view(bs_embed * 1, -1)

        return (
            prompt_embeds,
            negative_prompt_embeds,
            pooled_prompt_embeds,
            negative_pooled_prompt_embeds,
        )

    def check_inputs(
        self,
        prompt_embeds,
        negative_prompt_embeds,
        pooled_prompt_embeds,
        negative_pooled_prompt_embeds,
        image,
        controlnet_conditioning_scale=1.0,
    ):
        if prompt_embeds is None:
            raise ValueError("Provide `prompt_embeds`. Cannot leave `prompt_embeds` undefined.")

        if negative_prompt_embeds is None:
            raise ValueError("Provide `negative_prompt_embeds`. Cannot leave `negative_prompt_embeds` undefined.")

        if prompt_embeds.shape != negative_prompt_embeds.shape:
            raise ValueError(
                "`prompt_embeds` and `negative_prompt_embeds` must have the same shape when passed directly, but"
                f" got: `prompt_embeds` {prompt_embeds.shape} != `negative_prompt_embeds`"
                f" {negative_prompt_embeds.shape}."
            )

        if prompt_embeds is not None and pooled_prompt_embeds is None:
            raise ValueError(
                "If `prompt_embeds` are provided, `pooled_prompt_embeds` also have to be passed. Make sure to generate `pooled_prompt_embeds` from the same text encoder that was used to generate `prompt_embeds`."
            )

        if negative_prompt_embeds is not None and negative_pooled_prompt_embeds is None:
            raise ValueError(
                "If `negative_prompt_embeds` are provided, `negative_pooled_prompt_embeds` also have to be passed. Make sure to generate `negative_pooled_prompt_embeds` from the same text encoder that was used to generate `negative_prompt_embeds`."
            )

        # Check `image`
        is_compiled = hasattr(F, "scaled_dot_product_attention") and isinstance(
            self.controlnet, torch._dynamo.eval_frame.OptimizedModule
        )
        if (
            isinstance(self.controlnet, ControlNetModel_Union)
            or is_compiled
            and isinstance(self.controlnet._orig_mod, ControlNetModel_Union)
        ):
            if not isinstance(image, PIL.Image.Image):
                raise TypeError(f"image must be passed and has to be a PIL image, but is {type(image)}")

        else:
            assert False

        # Check `controlnet_conditioning_scale`
        if (
            isinstance(self.controlnet, ControlNetModel_Union)
            or is_compiled
            and isinstance(self.controlnet._orig_mod, ControlNetModel_Union)
        ):
            if not isinstance(controlnet_conditioning_scale, float):
                raise TypeError("For single controlnet: `controlnet_conditioning_scale` must be type `float`.")
        else:
            assert False

    def prepare_image(self, image, device, dtype, do_classifier_free_guidance=False):
        image = self.control_image_processor.preprocess(image).to(dtype=torch.float32)

        image_batch_size = image.shape[0]

        image = image.repeat_interleave(image_batch_size, dim=0)
        image = image.to(device=device, dtype=dtype)

        if do_classifier_free_guidance:
            image = torch.cat([image] * 2)

        return image

    def prepare_latents(self, batch_size, num_channels_latents, height, width, dtype, device):
        shape = (
            batch_size,
            num_channels_latents,
            int(height) // self.vae_scale_factor,
            int(width) // self.vae_scale_factor,
        )

        latents = randn_tensor(shape, device=device, dtype=dtype)

        # scale the initial noise by the standard deviation required by the scheduler
        latents = latents * self.scheduler.init_noise_sigma
        return latents

    @property
    def guidance_scale(self):
        return self._guidance_scale

    # here `guidance_scale` is defined analog to the guidance weight `w` of equation (2)
    # of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1`
    # corresponds to doing no classifier free guidance.
    @property
    def do_classifier_free_guidance(self):
        return self._guidance_scale > 1 and self.unet.config.time_cond_proj_dim is None

    @property
    def num_timesteps(self):
        return self._num_timesteps

    @torch.no_grad()
    def __call__(
        self,
        prompt_embeds: torch.Tensor,
        negative_prompt_embeds: torch.Tensor,
        pooled_prompt_embeds: torch.Tensor,
        negative_pooled_prompt_embeds: torch.Tensor,
        image: PipelineImageInput = None,
        num_inference_steps: int = 8,
        guidance_scale: float = 1.5,
        controlnet_conditioning_scale: Union[float, List[float]] = 1.0,
    ):
        # 1. Check inputs. Raise error if not correct
        self.check_inputs(
            prompt_embeds,
            negative_prompt_embeds,
            pooled_prompt_embeds,
            negative_pooled_prompt_embeds,
            image,
            controlnet_conditioning_scale,
        )

        self._guidance_scale = guidance_scale

        # 2. Define call parameters
        batch_size = 1
        device = self._execution_device

        # 4. Prepare image
        if isinstance(self.controlnet, ControlNetModel_Union):
            image = self.prepare_image(
                image=image,
                device=device,
                dtype=self.controlnet.dtype,
                do_classifier_free_guidance=self.do_classifier_free_guidance,
            )
            height, width = image.shape[-2:]
        else:
            assert False

        # 5. Prepare timesteps
        timesteps, num_inference_steps = retrieve_timesteps(self.scheduler, num_inference_steps, device)
        self._num_timesteps = len(timesteps)

        # 6. Prepare latent variables
        num_channels_latents = self.unet.config.in_channels
        latents = self.prepare_latents(
            batch_size,
            num_channels_latents,
            height,
            width,
            prompt_embeds.dtype,
            device,
        )

        # 7 Prepare added time ids & embeddings
        add_text_embeds = pooled_prompt_embeds

        add_time_ids = negative_add_time_ids = torch.tensor(
            image.shape[-2:] + torch.Size([0, 0]) + image.shape[-2:]
        ).unsqueeze(0)

        if self.do_classifier_free_guidance:
            prompt_embeds = torch.cat([negative_prompt_embeds, prompt_embeds], dim=0)
            add_text_embeds = torch.cat([negative_pooled_prompt_embeds, add_text_embeds], dim=0)
            add_time_ids = torch.cat([negative_add_time_ids, add_time_ids], dim=0)

        prompt_embeds = prompt_embeds.to(device)
        add_text_embeds = add_text_embeds.to(device)
        add_time_ids = add_time_ids.to(device).repeat(batch_size, 1)

        controlnet_image_list = [0, 0, 0, 0, 0, 0, image, 0]
        union_control_type = (
            torch.Tensor([0, 0, 0, 0, 0, 0, 1, 0]).to(device, dtype=prompt_embeds.dtype).repeat(batch_size * 2, 1)
        )

        added_cond_kwargs = {
            "text_embeds": add_text_embeds,
            "time_ids": add_time_ids,
            "control_type": union_control_type,
        }

        controlnet_prompt_embeds = prompt_embeds
        controlnet_added_cond_kwargs = added_cond_kwargs

        # 8. Denoising loop
        num_warmup_steps = len(timesteps) - num_inference_steps * self.scheduler.order

        with self.progress_bar(total=num_inference_steps) as progress_bar:
            for i, t in enumerate(timesteps):
                # expand the latents if we are doing classifier free guidance
                latent_model_input = torch.cat([latents] * 2) if self.do_classifier_free_guidance else latents
                latent_model_input = self.scheduler.scale_model_input(latent_model_input, t)

                # controlnet(s) inference
                control_model_input = latent_model_input

                down_block_res_samples, mid_block_res_sample = self.controlnet(
                    control_model_input,
                    t,
                    encoder_hidden_states=controlnet_prompt_embeds,
                    controlnet_cond_list=controlnet_image_list,
                    conditioning_scale=controlnet_conditioning_scale,
                    guess_mode=False,
                    added_cond_kwargs=controlnet_added_cond_kwargs,
                    return_dict=False,
                )

                # predict the noise residual
                noise_pred = self.unet(
                    latent_model_input,
                    t,
                    encoder_hidden_states=prompt_embeds,
                    timestep_cond=None,
                    cross_attention_kwargs={},
                    down_block_additional_residuals=down_block_res_samples,
                    mid_block_additional_residual=mid_block_res_sample,
                    added_cond_kwargs=added_cond_kwargs,
                    return_dict=False,
                )[0]

                # perform guidance
                if self.do_classifier_free_guidance:
                    noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
                    noise_pred = noise_pred_uncond + guidance_scale * (noise_pred_text - noise_pred_uncond)

                # compute the previous noisy sample x_t -> x_t-1
                latents = self.scheduler.step(noise_pred, t, latents, return_dict=False)[0]

                if i == 2:
                    prompt_embeds = prompt_embeds[-1:]
                    add_text_embeds = add_text_embeds[-1:]
                    add_time_ids = add_time_ids[-1:]
                    union_control_type = union_control_type[-1:]

                    added_cond_kwargs = {
                        "text_embeds": add_text_embeds,
                        "time_ids": add_time_ids,
                        "control_type": union_control_type,
                    }

                    controlnet_prompt_embeds = prompt_embeds
                    controlnet_added_cond_kwargs = added_cond_kwargs

                    image = image[-1:]
                    controlnet_image_list = [0, 0, 0, 0, 0, 0, image, 0]

                    self._guidance_scale = 0.0

                if i == len(timesteps) - 1 or ((i + 1) > num_warmup_steps and (i + 1) % self.scheduler.order == 0):
                    progress_bar.update()

        latents = latents / self.vae.config.scaling_factor
        image = self.vae.decode(latents, return_dict=False)[0]
        image = self.image_processor.postprocess(image)[0]

        # Offload all models
        self.maybe_free_model_hooks()

        return image